Ectoparasiticides 2 Flashcards Preview

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Flashcards in Ectoparasiticides 2 Deck (14)
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1

Lufenuron

Kills flea larva and eggs

2

Nitenpyram, Spinosad

Per os to kill adult fleas

3

Afoxolaner, fluralaner, sarolaner

Kills adult fleas and ticks

4

Cyromazine, diflubenzuron

Kills fly larva

5

Toxicity of Ectoparasiticides

1) they must be applied properly to minimize injury
2)*dermal absorption in animals
3) weak or young animals may respond differently to ectoparasiticides
4) MOST ARE HIGHLY LIPID SOLUBLE, AND THUS MAY CAUSE CNS DISTURBANCES
5) Anti-ChE poisoning: SLUDD

6

Ectoparasiticide: species sensitivity

1) horses: sensitive skin, easy to have urticaria, hyperemia
2) ruminants*: have approximately 50% of ChE of other species, should avoid anti-ChE or use a lower dose (susceptible to toxicity)*
- stay away from organophosphate in ruminants
3) cats: easy to get excited; drug metabolism problem; grooming
-*sensitive to synthetic pyrethroids and anti-ChE

*AVOID IN HOT AND HUMID WEATHER-stresses animal and can make toxicity worse

7

Formulations in feed products or oral form

1)*systemic toxicity more likely
2) trend to avoid this practice
3) very safe insecticides can be used this way

8

Major classes of Ectoparasiticides

1)**anti-cholinesterase agents: organophosphates, carbamates
2) insect growth regulators (IGR's): cyromazine, methoprene, pyriproxyfen
3) insect development inhibitors (IDI's): lufenuron, diflubenzuron
4) Botanicals: pyrethroids, rotenone (knockdown products)
5) macrocyclic lactones: ivermectin, selamectin, moxidectin
-nematodicides; also can kill arthropods

9

Major classes of Ectoparasiticides (cont'd)

1) *Octopamine receptor agonist: amitraz
2) nicotinic receptor agonists: imidacloprid, dinotefuran, nitenpyram, spinosad, spinetoram
-insecticides; these nicotinic receptor agonists have great affinity for insect receptors but not human or animal nicotinic receptors
3) *Cl- channel blocker: fipronil, afoxolaner, fluralaner, sarolaner
-depolarization, block influx of chloride, kill all arthropods (flea, tick, mites)
4)Na+ channel blocker: indoxacarb
-hyperpolarization of excitable cells
5) which ectoparasiticides can kill mites and ticks (arachnids)? - (acaracides - have an *)
6) most of them affect neuromuscular system of parasites

10

Drug interactions between ectoparasiticides

*Do NOT concurrently use a drug that causes depolarization with a drug that causes hyperpolarization

11

Organophosphates

1) can kill all arthropods
2)*on the way out!
3) very toxic in ruminants and cats!
4) serious toxicity problems: SLUDD, cardiac arrhythmias, fasciculations, ataxia, convulsions => sympathetic and parasympathetic NS activated (FORMING COVALENT BOND WITH AChE; PERSISTENT TOXICITY)
5) chronic toxicity: paralysis due to demyelination; rare

12

Treatment of organophosphate toxicity

1) atropine sulfate: in severe cases repeat every 3-4 hours
-**do NOT over treat! It can lead to G.I. atony. Cattle would be in big trouble
2) decontamination, supportive therapy

13

Pralidoxime (2-PAM)

1) does NOT cross BBB
2) use within 24 hours of exposure to organophosphate
-the OP will age-will change molecules and 2- PAM not effective
3)*must use with atropine!
-Atropine can cross blood-brain barrier!
4) 2-PAM pulls OP away from AChE and allows enzyme to be active again

14

Drug interactions of OP's

1) avoid drugs that affect acetylcholine receptors in CNS
-no cholinergic agonists
-no skeletal muscle relaxants
-no CNS stimulants, depressants